release_unlink_race.c

/*
  This program can be distributed under the terms of the GNU GPLv2.
  See the file COPYING.
*/
 
#define FUSE_USE_VERSION 31
 
#define _GNU_SOURCE
 
#include <fuse.h>
 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
 
static void *xmp_init(struct fuse_conn_info *conn,
                      struct fuse_config *cfg)
{
        (void) conn;
 
        cfg->use_ino = 1;
        cfg->nullpath_ok = 1;
        cfg->entry_timeout = 0;
        cfg->attr_timeout = 0;
        cfg->negative_timeout = 0;
 
        return NULL;
}
 
static int xmp_getattr(const char *path, struct stat *stbuf,
                        struct fuse_file_info *fi)
{
        int res;
 
        (void) path;
 
        if(fi)
                res = fstat(fi->fh, stbuf);
        else
                res = lstat(path, stbuf);
        if (res == -1)
                return -errno;
 
        return 0;
}
 
static int xmp_unlink(const char *path)
{
        int res;
 
        res = unlink(path);
        if (res == -1)
                return -errno;
 
        return 0;
}
 
static int xmp_rename(const char *from, const char *to, unsigned int flags)
{
        int res;
 
        if (flags)
                return -EINVAL;
 
        if(!getenv("RELEASEUNLINKRACE_DELAY_DISABLE")) usleep(100000);
 
        res = rename(from, to);
        if (res == -1)
                return -errno;
 
        return 0;
}
 
static int xmp_create(const char *path, mode_t mode, struct fuse_file_info *fi)
{
        int fd;
 
        fd = open(path, fi->flags, mode);
        if (fd == -1)
                return -errno;
 
        fi->fh = fd;
        return 0;
}
 
static int xmp_release(const char *path, struct fuse_file_info *fi)
{
        (void) path;
 
        if(!getenv("RELEASEUNLINKRACE_DELAY_DISABLE")) usleep(100000);
 
        close(fi->fh);
 
        return 0;
}
 
static const struct fuse_operations xmp_oper = {
        .init           = xmp_init,
        .getattr        = xmp_getattr,
        .unlink         = xmp_unlink,
        .rename         = xmp_rename,
        .create         = xmp_create,
        .release        = xmp_release,
};
 
int main(int argc, char *argv[])
{
        umask(0);
        return fuse_main(argc, argv, &xmp_oper, NULL);
}